Facebook’s fourth-quarter earnings results drop after the bell this afternoon, and Wall Street has high expectations for the social giant. The consensus estimate of analysts is earnings per share of 27 cents on revenue of $2.33 billion.

Beyond that, here are the three areas we’ll be watching when Facebook’s financials cross the wire:

Where’s the Ad Growth Coming From?

Facebook’s ad business has been consistently strong in the past, delivering steady year-on-year growth.

But here’s the thing — where’s the continued ad dollar growth going to come from? Sticking more ads into the News Feed? (That’s something Ebersman said wouldn’t be happening last quarter.) Creating new, “better” types of ads? (Entirely possible, given the supposed success of mobile app install ads.) We don’t know, and a bit more elucidation on that point would be nice.

Mobile, Mobile, Mobile — Ads, Specifically.

In just one year, Facebook’s mobile advertising has surged, starting from bringing in absolutely no revenue to now accounting for more than half of the company’s ad business.

We want to know why, and my colleague Peter Kafka has a hunch that Facebook’s mobile app install advertising product — which directs users out from the News Feed to download applications from the App Store and Google Play — is playing a big part in that success. Perhaps Ebersman or Sandberg will give a little more detail on the future of this product (something they’ve been reluctant to do in previous quarters) as well as any other mobile ad plans the company has.

Check back later this afternoon, as Peter and I will be reporting on the numbers and the conference call.